High density encapsulation



Dec. 25, 1956 Filed June 19, 1953 F. E. STIRN ET AL 2,775,081

HIGH DENSITY ENCAPSULATION 6 Sheets-Sheet l MIL Wm ATTO R N EY 1956 F.E. STIRN ET AL 2,775,081

HIGH DENSITY ENCAPSULATION Filed June 19, 1953 6 Sheets-Sheet 2 M WWWDec. 25, 1956 F. E. STIRN ET AL 2,775,081

HIGH DENSITY ENCAPSULATION Filed Junel9, 1953 6 Sheets-Sheet 3 INVENTORSFiAW/r f. JT/AN,

ATTO R N EY Dec. 25, 1956 F. E. STl RN ET AL 2,775,081

HIAGH DENSITY EINCAPSULATION 6 Sheets-Sheet 4 Filed June 19, 1955 63% RR1 n o r N T 4 R ma? #0 m w [KP A 3 P7 1956 F. E. STIRN ET AL 2,775,031

HIGH DENSITY ENCAPSULATION Filed June 19, 19.53 6 Sheets-Sheet 5INVENTORS F/Pfl/VK E. sr/A /v AZTOANEY HI GH DENSITY ENCAP ULATION FiledJune 19, 1953 6 Sheets-Sheet 6 United States Patent HIGH DENSITYENCAPSULATION Frank Edwin Stim, Pearl River, and Arthur Sinclair Taylor,Spring Valley, N. Y., assignors to American (lg/air amid Company, NewYork, N. Y., a corporation of Maine Application June 19, 1953, SerialNo. 362,926

20 Claims. (Cl. Sit-650) This invention relates to improvements in amethod and an apparatus for forming and filling capsules from a strip ofplastic sheet material, such as soft gelatin, with a pro-compacted highdensity powder substance.

In the past, it has been customary when administering a powdermedication to patients to fill the powder loosely into a two-piecetelescopic hard gelatin capsule. Such a capsule necessarily has acomparatively low density of powder. These hard shell capsulesfrequently come apart, and are not tamper-proof. It has also beencustomary to package liquids in soft gelatin capsules formed from stripsof soft gelatin. Our earlier patents disclose methods of filling suchsoft gelatin capsules with a loose powder.

In many instances, it is desirable to be able to ,ad ministercomparatively large dosages of powder to a patient and, particularly, ifthe powder has a disagreeable taste or if it is deleterious to thetissues of the mouth, it is desirable that the powder be placed in acapsule, so that the capsule releases the powder after passing themouth. For such powders it may be desirable to be able to compact asmuch powder as possible into a minimum size of dosage unit forconvenience in administration. While it is known to the medicalprofession that comparatively large objects may be readily swallowed,the average patient has a psychological block against trying to swallowlarge capsules.

Hexylresorcinol capsules have been made by sealing hexylresorcinol pillsbetween gelatin sheets in a batchwise essentially symmetrical operationas is disclosed by patents to P-ittinger, Nos. 2,155,444 and 2,155,445Such a batchwise process involving, as it does, the distribution of thehexylresorcinol pills between preformed sheets of gelatin is a slow,tedious labor-consuming operation.

It is possible by the use of the apparatus and methods of this inventionto continuously produce solid filled, soft gelatin capsules of not onlyround but also elliptical or long oval configuration at a high rate ofspeed without the necessity for hand labor.

The machine of our invention makes practical the method of filling thecapsules by compacting a powder into a tablet or slug. The slugs arepreferably approximately rounded, and may be either circular orelliptical. They are fed through a magazine into cavities lined with astrip of plastic sheet material in a rotating die roll. After thedeposition of the slug in the plastic strip-lined cavity, a secondplastic strip is placed in juxtaposition to the first, covering theslug, after which cutting edges penetrate the two strips, simultaneouslysealing and cutting out the portions of the strips surrounding theslugs, thereby giving uniform symmetrical high density powder-filledcapsules.

The slugs themselves may be formed by using standard tableting machineswith dies for forming slugs of the desired shape. While other shapes maybe used, ranging from spheres to lens-shaped tablets or football-shapedtablets, i. e., both oblete and prolete spheroids, what is known in thetrade as long ovals, namely, a cylindrical portion with twohemispherical ends is generally preice ferred as giving a maximum volumewith a minimum diameter. By appropriate dies fora tableting machine, theappropriatesized and shaped slugs are easily formed. Slightly flat sidesmay be formed on the slugs due to the characteristics of the tabletingmachine, and such slugs are easily encapsulated by the machine of thisinvention. We find it convenient to store the slugs, without regard fororientation, in containers until ready for use.

In feeding our machine, we use a vibratory bowl feeder which consists ofa bowl into which the slugs are poured with peripheral channels aroundthe bowl, and because of the rotary vibratory motion of the bowl, theslugs travel to the rim of the bowl and around the bowl in theperipheral channels, and from them, in turn, to feed tubes which may beeithersolid tubes or spiral springs, and thence into the slug-feedingmagazines. The tubes must be of slightly greater diameter than themaximum crosssection diameter of the slugs, but should be small enoughso that the slugs cannot start to pass each other and jam. Slugs withpointed ends may lodge obliquely in the tube and impair the feeding iftoo large a tube is used.

Such vibratory feeders are disclosed in U. S. patents to Weyandt, Nos.2,187,717; 2,305,943; and to Devol, No. 2,464,216, and are soldcommercially. Other forms of feeders which deliver oriented slugs at auniform rate may be used. The slugs are fed through the feed tubes intothe top of the magazines, where they orient themselves. For theelliptical and long oval slugs, the magazine is long enough that themajor axis tends to assume the horizontal. For lens-shaped slugs, theslugs tend to become horizontal. In each instance, the center of gravitytends to assume the lowest position. The vibration which is conductedfrom the vibratory feeder to the slug-feeding magazines through thetubes aids in the orientation of the slugs. An additional vibrator maybe used. Care must be taken if two vibratory sources are used that thevibratory motions are not permitted to oppose each other and formstanding waves .01 nodes at such points as would hamper the uniformfeeding of the slugs.

The die roll beneath the slug-feeding magazine may be constructed fromone piece or built up and is preferably a cylindrical die with pluralityof uniformly spaced, uniformly shaped cavities, each with a. positiveejection means and a raised cutting-out rim and of such size that aplastic strip when placed on the surface of the die roll may be drawninto and caused to line the cavity with an interior size which isslightly larger than the slug, so that the slugs may uniformly drop bygravity into the striplined cavity.

The strip material is conveniently of a gelatin composition consistingof gelatin, glycerin, and water, together with such pigments, dyes andperfumes as may be aesthetically desirable with preservatives andhardening agents as desired. Gelatin substitutes, such as edibleplastics, may be used when available and economically practical. Stripsof such compositions are well known to those skilled in the art, as arethe machines for easting and forming the strips. The strips may becoated on the outside with a lubricant, such as a mineral oil orkerosene, preferably deodorized, or a mixture thereof, so that thestrips will not adhere to the die roll or the seal roll or yet will notslide unduly thereon. The side of the strip which forms the interior ofthe capsule may be coated with gum benzoin, or shellac, gum sandarac, orother material to assist in preventing the materials of the slug frominter-acting with the material forming the strip. Some vitaminaceousfillingmaterials have a tendency to discolor the strip material orinter-act with the moisture of the strip material.

The strip is fed over the cavity die roll and by. suction drawn downinto the cavities therein. As the strip material-lined cavities passbeneath the slug-feeding magazine, a single slug drops from the magazineinto each cavity, thereby, substantially filling the cavity andretaining the remaining slugs in the magazine until the next emptycavity in turn passes beneath the magazine. As the slug-containingcavities rotate,'a covering strip is placed thereover. A separate rollmay be used to place the covering strip over the filled cavities, but wefind it particularly convenient to use a sealing roll both to feed thecovering strip and to seal and cut out the capsules. The temperature ofthe seal roll is normally slightly higher than the die roll which causesthe sealing portion of the strip to be somewhat more tender than thestretched portion lining the cavity. Thereby, when the film-covered slugis released from confinement, the warmed portion is stretched, as thepocketed portion shrinks so that the sealing line is drawn down to thecenter line of the slug and a symmetrical covering is produced. Byadjusting the temperature of the seal roll slightly, the position of theseal line may be adjusted so as to obtain an equatorial seal.

The seal roll may have recesses, so that the cavities in the cavity dieroll need not be so deep, as the slugs extend partially up into theserecesses. be drawn into thermal contact with the sealing roll for asufiicient time that it is uniformly warmed so that in the relief ofstresses, it is uniformly stretched.

If the depressions in the seal roll are somewhat smaller than the areaof the cavities, as for example when the depressions are adapted tocontain only a small portion of the slug during sealing, it isunnecessary to draw the strip into the depression. If the Width of thefilm contacting portion of the seal roll inside of the die rimcontacting portion exceeds about inch (0.8 millimeter), adequate thermalcontact is obtained. With less than this, a thin heated line isobtained, which stretches unduly and shows thin spots in the slugcovering film.

The amount of air trapped with the slug varies with the size and theshape of the cavity. If the holding vacuum, which retains the cavitylining strip in position is released just prior to the sealingoperation, a minimum of air is trapped with the slug in the finishedcapsule. A small amount of air usually gives a more resilient and lesseasily damaged finished product. By adjusting the point at which thevacuum is released in the sealing operation, the amount of trapped airmay be very easily controlled. The film should preferably appear firmlybut not tightly stretched around the slug.

Previously, designers of capsule-forming machines have found itdifficult to remove the finished capsules from the cut-out residual web,or net. In the present machine because the cavity die rolls havecavities which are comparatively deep as compared with prior artmachines, it is possible to hold the residual strips, now forming aperforated web or net, against the surface of the cavity die roll andeject the capsules and brush them off from the surface of the die rollbefore the web is released. It is preferred, however, to retain thecapsules in the cavities by the application of a holding vacuum, andstripping the web oif by a slight tension, so that the residual netremains on the sealing roll until separated from the capsules and isdrawn E to be re-processed. The capsules remaining in the cavities maythen be ejected at a convenient portion of their travel around theperiphery of the cavity die rolls, conveniently by the positive actionof plugs within the cavities. With round or elliptical capsules, thereis little danger of the capsules sticking in the cavities, but with longoval capsules in particular, it is desirable to have a positive actingejector plug at each end to ensure that neither end of the capsuleremains stuck in the die roll. Air-operated plungers are particularlyconvenient for this purpose, and uniform, reliable, and effectiveejection may be thus obtained.

Conveniently, the capsules may be ejected into a capsule receivinghousing which at its lower portion has a pneumatic conveyor which picksup and carries the The covering strip may 4 capsules to a tumbling drumor receiving tray or other desired location.

The invention is further described in connection with particularembodiments thereof in the accompanying drawings.

Figure 1 is a side elevation.

Figure 2 is a pictorial representation, showing how the strip materialis drawn into the cavities and the slugs are fed thereinto.

Figure 3 is a sectional view through a portion of the cavity die rollshowing how the slugs feed from the slugfeeding magazine into thestrip-lined cavities.

Figure 4 is a detailed view showing a slug directly beneath themagazine.

Figure 5 shows the slugs as the die roll rotates past the magazine.

Figure 6 shows a later stage in rotation in which a slug rests on thesurface of the strip during a dwell period.

Figure 7 shows how at the end of the dwell period the next slug slipsinto the next cavity.

Figure 8 shows a second embodiment with deeper cavities in the die roll,wherein the entire slug is received within the cavity.

Figure 9 is a partial view of the embodiment of Figure 8 showing acavity directly beneath a magazine.

Figure 10, at a slightly later time, shows the magazine over an intervalbetween cavities.

Figure 11, still later, shows an approaching strip-lined cavity as itreceives its slug.

Figure 12 shows a particular magazine having access slots in its face,so that improperly oriented slugs fall out.

Figure 13 shows the sealing action of a recessed seal roll of the firstembodiment of the invention.

Figure 14 shows a smooth seal roll in sealing relationship with thedeeper cavities of the second embodiment.

Figure 15 is a view of the manifolding plate for a die roll.

Figure 16 is a sectional view along lines 16-16 of Figure 15.

The machine may be designed for any size and shape of the completedcapsule. The die roll and seal roll may be changed for various sizes ofcapsules. The machine will be described in connection with the fillingof a particular long oval capsule in which the length of the slug isover twice its diameter. The slugs need not be completely round, and intableting presses, it is frequently found convenient to have slightlyfiat sides as the forming dies are more easily manufactured for thisshape. However, for purposes of illustration, the slugs are shown asround and symmetrical.

In Figure 1 a lower plastic strip 21 is supplied from a suitable castingsource and is a fresh, soft, thin gelatin film. The strip passes over anoil roll 22. The oil roll is in turn kept oiled by contact with the oilfeed roll 23 which rotates partially submerged in an oil bath 24. Asuitable oil supply system may be attached to the oil bath to maintainthe oil at a constant level therein. A thin mineral oil or a mineral oilthinned with a deodorized kerosene may be used. After passing over theoil roll, the film passes under a positioning roll 25 into contact withan inside coating roll 26, which roll is in turn fed by an insidecoating feed roll 27 which rotates in a coating trough 28. It ispreferred that the rolls contacting the strip be driven by a suitabledrive means so that all stresses in the strip are kept at a minimum. Theplastic strip next contacts the cavity die roll 29. The cavity die rollis shown in Figures 1 and 2 and in partial section in Figures 3 and 13.The die roll may be engraved from a single metal blank but is moreconveniently built up in structure as is shown in Figure 3. It consistsof a die roll blank 30, which has around its periphery a series of slotswhich contain the capsule cavity inserts 31. Underneath the capsulecavity inserts are the capsule ejector plugs 32, which fit into holes inthe bottom of the capsule cavity inserts and extend down into ejectorpiston cylinders 33. On the bottom .of each of the plugs is a capsuleejector piston 34. One end of the piston cylinder is connected by amanifold 36 to a source of pressure or vacuum which is applied throughthe valve plate 35. The ejector piston has a small piston slot .37 in itso that the piston head cannot form an air tight seal against the bottomof the cylinder.

The pistons and plugs are fitted with sufficient clearance that a vacuumapplied beneath the piston will hold the piston and plug in thewithdrawn position, and also draw the strip laid over the surface of thedie roll down into the cavities. A clearance of .008 inch (0.2millimeter) gives excellent results, and also prevents binding of theplug and cylinder. The length of the plug in the cylinder is such thatin raised position the top of the plug is approximately even with thetop surface of the capsule cavity insert. The length is not critical.The capsule cavity inserts for the long oval capsules are something likea bath tub in configuration having a cutting rim 38 extending above thelevel of the die roll blank. The top surface of these cutting rims formthe cylindrical periphery of the cavity die roll. The rim hassemi-circular ends and a straight connecting portion on each sidebetween these ends. The capsule cavity inserts are made of hardenedsteel in order that a maximum of wear may be obtained before it isnecessary to grind the rims. The rims are under considerable pressureand gradually wear out. Small nicks in the rims cause defects in thecutting out operations. The capsule cavity inserts are vshown retainedin the die roll by a pressure fit. Mechanical fasteners may be used.

Above the cavity die roll is a slug feeding magazine 39. As shown inFigure 2, this has two slug channels 40, each of which is slightly widerthan the length of the slug 93 and each of which has a depth slightlygreater than the diameter of the slug. The magazine has a transparentslug retaining magazine cover 41, preferably of a transparent plastic sothat the passage of the slugs through the magazine may be observed. Themagazine is held in place by a magazine support 42, to which a retaininglug 43 of the magazine is fastened. Retaining bolts 44 are used whichare drawn up tight and then backed off enough that the magazine isloosely held in place, so that it may vibrate without being displaced.The vibration induced in the magazine from the bowlfeeder, which islater described, aids in causing the slugs 93 to attain a uniform,ordered, parallel orientation within the slug channels.

Each of the slug channels 40 has leading thereto aslug feeding tube 45which is a tube of slightly. greater diameter than the slugs throughwhich the slugs are fed axially from a bowl feeder 4-6. The bowl feeder,a commercially available item, as before mentioned, has a bowl in whichthe slugs are dumped, which is vibrated by an electromagnetic vibrator47, so that the slugs in the bowl are shaken thus causing them to orientthemselves upon peripheral ledges in the bowl and travel along these.ledges to the slug feeding tubes and through the slug feeding tubes tothe magazine. The vibration induced through the tubes from the vibrationof the bowl causes the slugs to feed smoothly through the tubes and alsocauses the slugs to feed uniformly through the magazine.

In the face of the transparent slug retaining magazine cover 41 areapertures 48 which permit the operator to orient the slugs in themagazine should they become disarranged. Usually, it is necessary toorient the slugs in starting up the machine, but once the magazines havebeen filled with oriented slugs, they retain that orientation,subsequentslugs orient themselves, and no difliculty is found in thecontinuing operation.

The lower plastic strip is drawn into the individual capsule cavityinserts by reducing the pressure inside the cavities. As shown in Figure3, the strip may be drawn down into the inserts just before the insertspass under the magazine. As shown in Figures 3 and 4, the bottom slugfrom the magazine drops into the strip lined insert and remains at such.a height as to prevent additional slugs from escaping from themagazine. As the die roll rotates in the direction shown by the arrows,the slug in the strip lined cavity passes out from under the magazine,and the group of slugs in the magazine are permitted todescend as shownin Figure 5. As a preceding slug containing cavity continues to rotate,Figure 6, the bottom slug then comes in contact with the strip betweencavities and slides along this surface until the suc ceeding cavitypasses under the magazine. As shown in Figure 7, the following slugstarts to drop into the following cavity as the following cavity passesunder the magazine. When the slug has fallen completely into the cavity,it is retained therein as shown in Figure 4 and the process repeated.Conveniently, two rows of cavities are contained in the die roll,although any number may be used, and are in staggered relationship, sothat they may be more closely placed, and the loss of strip material inthe residual net is minimized.

As the slug-containing, strip :lined cavities rotate, an upper plasticstrip or second strip of plastic sheet material 49 .is fed wunder aninside coating roll 5t), which in turn contacts a coating feed roll El,which contacts a transfer roll 52, which contacts a partially submergedroll 53, which. rotates in a coating trough 54. The strip then contactsa release coating roll 55, which coats the outer surface of 'the upperstrip with a thin coating of a releasing agent, such as a deodorizedkerosene, as is more fully described and claimed in our copending Patent2,674,073, Relieved Non-skid Seal Roll and Method of Use, April 6, 1954.If mineral oil is used at this point, the upper strip may skid on thesurface of the seal roll and slide, thereby giving distorted shapes tothe capsules. This coating may be applied directly to the surface of theseal roll. The strip is then laid on the surface of the seal roll 56.The seal roll 56 has sealing depressions 57 in its surface and so spacedas to cooperate with the cavities in the face of the cavity die roll. inthe modification shown in Figure 13, the slugs extend above the surfaceof the die roll, so that in sealing it is necessary to have thedepressions inthe sealing roll to permit the slugs to partially extendthereinto.

The depressions must be at least deep enough so that the combined depthof the depression and the cavity is at least equal to the maximum slugdiameter plus the thicknesses of both strips.

Vacuum manifold passages 58 extend from the bottoms of these recesses toa face of the die roll, so that a vacuum may be drawn in the individualrecesses to cause the second strip to smoothly contact not only theouter face of the die roll but also the surface in the recesses. Forbest results, the die roll is at a slightly warmer temperature than thecavity roll, and thereby, the upper strip is warmed. For uniform Warmingof the strip, the strip must contact the seal roll at all portions, andtherefore, sufiicient vacuum must be used to draw the upper plasticstripintouniform contact with the seal roll.

A thermostatically controlled electric heating element 94 is used tokeep the seal roll at a desired temperature. The temperature may beraised or lowered to adjust the degree of stretching of the portion ofthe second strip forming part of the capsule, and hence control thesymmetry of seal.

The seal roll and the cavity die roll approach and contact .each other,the raised rims of the cavities of the cavity die roll coming intocontact with the surface of the seal -roll. The strips on the surface ofthe two rolls are thus brought into contact with each other, and thenthe cutting rims 38 of the cavities cut through the two strips, therebycausing them to seal to each other. The operation also severs the thuscut'out portions, which then cover the slug, from the remainder of thestrips. As showniin Figure 13, the lower plastic strip is drawn downinto the cavity die roll as it approaches the sealing roll position; atposition A, the vacuum is broken slightly before the rolls come incontact, which permits the elasticity of the strip to cause the strip toattempt to rise, and thereby, hug against the slug as is shown atposition B. The vacuum release point is adjusted so that the slugs arenot thrown out of the cavities before the upper strip comes in contactwith them. The amount of air trapped with the slug can be varied bychanging the vacuum release location. As shown in the next position, theslug at C has both the upper and the lower strips firmly placed aboutit, and the rim has cut uniformly through the strips at the front of thecapsule, but the cutting-out rim has not yet completely severed thestrips at the rear of the capsule. In the next position at D, it is seenthat the capsule has been completely out out, and the residual Web nowforming a net is held against the seal roll and withdrawn from thecapsules which are then held in the cavities by a holding vacuum atapproximately the point D.

It may be seen that because the seal roll is above the equatorialdiameter of the slug, the recess may be a little smaller than theopening in the capsule cavity inserts, and accordingly, any minor errorsin positioning between the seal roll and the cavity die roll does notdeleteriously affect the seal. Preferably this overlap is wide enough toassist in heat transfer to the second strip.

The finished capsules are retained in the cavities as they rotate aroundto a capsule receiving housing 59. As the cavity in the die roll passesinto the receiving housing pressure is applied within the cylinder underthe cavity causing the pistons and the attached plugs to rise, forcingthe capsule out of the cavity and into the housing. As the capsules fallinto the housing, a pneumatic conveyor 60, which consists of a travelingair jet as reduced pressure picks up the falling capsules and tumblesthem through a discharge tube 61. The discharge tube may be adjusted tofeed into any desired receiver. The residual strips now form a net 62.The net passes over an idler roll 63 to the net draw otf rolls 64 whichare driven at a slightly faster surface speed than the surface speed ofthe die roll. The net as it feeds from these rolls may be fed to atake-up reel or a container for storage or re-use. It is convenient toremelt the net and use the material subsequently in forming capsules.

The various rolls may be support for a frame 65, which isdiagrammatically shown as having the proper supports at the desiredlocations for the various elements previously mentioned. It isconvenient to have the seal roll pressed against the surface of the dieroll by hold down pins 66, which are urged by a spring 67 againstbearings 68 on the seal roll shaft 69. The pressure between the rollsmay be thus easily adjusted, and the springs permit any slightvariations in the surfaces of the rolls to even out without unduly heavypressure being exerted at a particular point.

The die roll 29 has on its face the valve plate 35. As shown in Figure15, for the plate on the back side of the machine, a vacuum chest 70 isarranged to contact the ends of the manifold connected to the ejectorpistons and hold down the plastic strip from the time shortly after itfirst contacts the cavity die roll until just before the sealingposition. A vacuum connection 71 leads to a suitable vacuum source. Asecond vacuum chest 72 again applies a vacuum to hold the capsules inthe cavities as the Web is removed. A second vacuum connection 73connects this vacuum chest to the vacuum source. A pressure chest 74with a pressure connection 75 is in such a location as to connect to themanifold passages and in turn the pistons so that the plugs are raisedand the capsules ejected as the cavities pass the capsule receivinghousing 59. A balancing chest 76 extends around the periphery of thevalve plate and has therein a vacuum connection 77. The vacuum in thisbalancing chest is used to maintain a balance on the plate and keep thepressure in the pressure chest and the otherwise unbalanced vacuumacting on the other side of the plate from lifting or turning the plate.A valve plate positioning bracket 78 extends from the edge of the plate,so that the plate may be angularly positioned by the positioning screws79; the adjustment of these screws controls the point at which thevacuum is released during the sealing step and thus controls the amountof air which is trapped in the capsule.

Smooth seal roll die syst m Figures 8 to 12 and 14 show a modificationof the die roll system in which the individual capsule cavity insertsare sufiiciently deep that a smooth seal roll rotates in contact withthe surface of the die roll and the entire plastic strip covered slug isbeneath the top surface of the capsule cavity inserts. This modificationpermits the use of smooth seal rolls. The heat transfer to the seal rollis more convenient, and the problems in timing are markedly reduced. Theshallow seal rolls are particularly convenient in slug encapsulation inthat the same capsule cavity seal roll which is used for filling liquidsor powders. The deeper cavity die rolls, which are deep enough tocompletely contain the strip covered slugs, are deeper than is normallydesired with a liquid or straight powder fill.

As shown in Figure 8, capsule cavity inserts 8t) fit into the cavity dieroll blank 81. Restricted orifices 82 extend from the bottom of thecapsule cavity inserts and are of such size that jets of air throughthem may be used for ejection without a complete loss of pressure beingpermitted through one open orifice. Inasmuch as there are no movingparts, there is nothing to stick. This form of ejection is particularlyconvenient with spherical or elliptical capsules. The depth of thecavity in the insert is deep enough so as to completely contain thestripcovering slug. As shown in Figure 8, the strip is sucked partiallyinto these cavities as the slugs are fed down thereinto. By using areduced vacuum and adjusting it properly, the strip is only partiallysucked into the insert, and the strip itself acts to seal off theorifice before the strip is pulled into the corners of the insert. Ifthe strip is not drawn down deep enough, the action of the sealing rollwill press the slug down into the cavity, and smooth operation isthereby obtained.

As shown in Figure 8, the magazine 83 has a slug retainer 84 in a slot85. A limiting screw 36 fits in a limiting slot 87 in the retainer, sothat the retainer can neither be pressed in too far nor drawn out toofar. The retainer may be pressed forward to restrain the supply of slugsduring starting and stopping of the machine or if for any reason it isdesired to operate the machine in manufacturing empty capsules. Instarting operation it is particularly convenient to manufacture emptycapsule shells until the temperature conditions and the sealingconditions are adjusted to give proper seals and thus avoid wasting ofthe slugs in defective capsules. The use of the slug retainers permitindependent adjustment of the slug feeding and the strip feedingmechanisms.

As more clearly shown in Figure 12, the magazine 83 has a transparentcover 88, through which the slugs may be seen. Rejection slots 89 arecut in this transparent cover so that any slugs which are non-paralleland which would, otherwise, tend to jam the feed may fall through theserejection slots to a return chute 90, which throws them off to the sideof the machine from which they can again be recycled to the bowl feeder.Figures 9, l0 and 11 illustrate the feeding of slugs from thisparticular magazine into the full depth capsule cavity inserts, showingin Figure 10 how the slugs ride along the surface of the strip on theface of the cavity die roll until as shown in Figure 11 the bottom slugdrops into the subsequent strip-lined cavity.

It is preferred that the strip not be drawn completely into the cavity,so that as shown in Figure 9 the falling slug does not drop below thelevel of the top of the strip on the face of the cavity die roll as,otherwise, the trailing edge of the capsule cavity would have to liftthe slugs in the magazine by a camming action as the cavity die rollrotates. In many instances, this type of action may occur to some extentwithout damage, but particularly with soft slugs, there is always adanger of breakage. Figure 14 shows the sealing action on the full depthcavity. The smooth surface seal roll 91 brings the upper plastic strip92. down against the cutting out faces of the capsule cavity inserts andsmoothly and uniformly cuts out the strips around the slugs. As shown inFigure 14, cavity A has the strip drawn down until it contacts theorifice 82 the bottom of the insert. In position B the the vacuum isreleased and the strip is permitted to draw up against the slug. Inposition C the sealing strip is pressed down against and sealed to thelower strip. A certain amount of air is usually trapped with the slug.The amount of air can be varied by changing the release point of thevacuum, but usually enough air is trapped so that the plastic strip liesloosely against the slug giving a smoother and evenly wrappedconfiguration to the capsule and preventing the appearance of askin-tight, stretched appearance.

It tight wraps are desired, a small nick may be cut in one edge of thecapsule-cavity inserts, so that a small hole is left in the seal line,which permits any trapped air to escape as the plastic strip drawsitself against the slug and hardens.

The ejection and discharge of the finished capsules may be the same asin the previously described modification.

T-he piston and plug or the orifice ejection system may be used witheither type of die roll-sealing roll system. Similarly, the details ofthe slug magazine for either modification may be interchanged.

Other modifications and minor changes in apparatus will suggestthemselves to those skilled in the capsuletorming art. Such minormodifications and changes are part of our invention as set forth in thefollowing claims.

We claim:

1. A method of forming plastic film covered precompacted powder-filledcapsules which comprises, compacting a powder into long oval slugs,placing a plurality of said slugs in a vibratory feeder bowl, vibratingsaid bowl, thereby causing said slugs to feed serially axially, passingthe slugs serially axially through a vibrating feed tube, feeding theslugs end-wise into a magazine, vibrating said magazine, by droppinggravity to a predominantly horizontally aligned position with aplurality of the sings in parallel oriented stacked relationship,dropping past clongated apertures permitting selective hand elignhig oislugs, shaking out by vibration through said apertures misaligned slugs,collecting and re-using the shaken out slugs, and continuing to drop thestack of slugs until adjacent to the hereinafter reciter recesses,laying a first continuous strip of plastic sheet material over aplurality of capsule forming cavities in a cavity die roll, reducing thepressure within the cavities, thereby drawing the first strip down intothe cavities to form a series of recesses, continuously passing saidseries of such recesses under the stack of slugs, dropping a slug atleast partially into each recess as said recess passes under the stackof slugs, thereby positioning a slug in each recess, moving the slug inits associated recess from under the stack of slugs, warming a secondcontinuous strip of plastic sheet material, placing said second strip injuxtaposition to said slug-containing recessed first strip, maintainingthe reduced pressure within the cavities until just prior to theemplacement of the second strip, raising the pressure in the cavities,thereby releasing the first strip and permitting it to shrink againstthe slugs as the cavities approach a sealing position, sealing togetherand cutting out the portions of said strips surrounding each slug,re-applying a reduced pressure within the cavities to retain thecapsules therein, pulling the net, consisting of the residual portionsof the two strips, away from the capsules retained in the cavity dieroll, ejecting the capsules from the cavities, and permitting thecut-out portions of the strips by the release of differential strainsinduced by the heating of the second strip, to adjust the capsules to asymmetrical final form.

2. A method for forming plastic film covered preconipacted powder-filledcapsules which comprises, compacting a powder into slugs, pie-forming aseries of recesses in a first continuous strip of plastic sheetmaterial, stacking said slugs in contacting, oriented relationship, withthe bottom slug supported on said strip, continuously passing saidseries of such recesses under said stack of said slugs, dropping a singat least partially into each recess as said recess passes under thestack of slugs, thereby positioning a slug in each recess, moving theslug in its associated recess from under the stack of slugs, placing asecond continuous strip of plastic sheet material in juxtaposition tosaid slug-containing recessed first strip, and sealing together andcutting out the portions of said strips surrounding each slug.

3. The method of claim 2 which comprises coating the sides of both thefirst and second continuousstrips of plastic sheet material which are tocontact the slug and form the interior of the capsule with an insidecoating material.

4. A method for forming plastic film covered precompacted powder-filledcapsules which comprises, compacting a powder into long oval slugs,placing a plurality of said slugs in a vibratory feeder bowl, vibratingsaid bowl, thereby causing said slugs to feed serially axially, passingthe slugs serially axially through a vibrating feed tube, feeding theslugs end-wise into a magazine, vibrating said magazine, dropping bygravity to a predominantly horizontally aligned position with aplurality of the slugs in parallel oriented stacked relationship,dropping past elongated apertures permitting selective hand aligning ofthe slugs, shaking out by vibration through said apertures this-alignedslugs, collecting and re-using the shaken out slugs, and continuing todrop the stack of slugs until adjacent to the hereinafter recitedrecesses, pre-forming a series of recesses in a first continuous stripof plastic sheet material, continuously passing said series of suchrecesses under a stack of said slugs, dropping a slug at least partiallyinto each recess as said recess passes under the stack of slugs, therebypositioning a slug in each recess, moving the slug in its associatedrecess from under the stack of slugs placing a second continuous stripof plastic sheet material in juxtaposition to said slug-containingrecessed first strip, and sealing together and cutting out the portionsof said strips surrounding each slug.

5. A method for forming plastic film covered precompacted powder-filledcapsules which comprises, compacting a powder into long oval slugs,placing a plurality of said slugs in a vibratory feeder bowl, vibratingsaid bowl, thereby causing said slugs to feed serially axially, passingthe slugs serially axially through a vibrating feed tube, feeding theslugs end-wise into a magazine, vibrating said magazine, dropping bygravity to a predominantly horizontally aligned position with aplurality of the slugs in parallel oriented stacked relationship,dropping past elongated apertures permitting selective hand aligning ofthe slugs, shaking out by vibration through said apertures mis-alignedslugs, collecting and re-using the shaken out slugs, and continuing todrop the stack of slugs until adjacent to the hereinafter recitedrecesses, laying a first continuous strip of plastic sheet material overa plurality of capsule forming cavities in a cavity die roll, reducingthe pressure within the cavities, thereby drawing the first strip downinto the cavities to form a series of recesses, continuously passingsaid series of such recesses under a stack of said slugs, dropping aslug at least partially into each recess as said recess passes under thestack of slugs, thereby positioning a slug in each recess, moving theslug in its associated recess from under the stack of slugs, placing asecond continuous strip of plastic sheet material in juxtaposition tosaid slug-containing recessed first strip, and sealing together andcutting out the portions of said strips surrounding each slug.

6. A method for forming plastic film covered precompacted powder-filledcapsules which comprises, compacting a powder into slugs, laying a firstcontinuous strip of plastic sheet material over a plurality of capsuleforming cavities in a cavity die roll, reducing the pressure within thecavities, thereby drawing the first strip down into the cavities to forma series of recesses, stacking said slugs in contacting, orientedrelationship, with the bottom slug supported on said strip, continuouslypassing said series of such recesses under said stack of said slugs,dropping a slug at least partially into each recess as said recesspasses under the stack of slugs, thereby positioning a slug in eachrecess, moving the slug in its associated recess from under the stack ofslugs, placing a second continuous strip of plastic sheet material injuxtaposition to said slugcontaining recessed first strip, maintainingthe reduced pressure within the cavities until just prior to theemplacement of the second strip, raising the pressure in the cavities,thereby releasing the first strip and permitting it to shrink againstthe slugs as the cavities approach a sealing position, and sealingtogether and cutting out the portions of said strips surrounding eachslug.

7. A method for forming plastic film covered precompacted powder-filledcapsules which comprises, compacting a powder into slugs, laying a firstcontinuous strip of plastic sheet material over a plurality of capsuleforming cavities in a cavity die roll, reducing the pressure within thecavities, thereby drawing the first strip down into the cavities to forma series of recesses, continuously passing said series of such recessesunder a stack of said slugs, dropping a slug at least partially intoeach recess as said recess passes under the stack of slugs, therebypositioning a slug in each recess, moving .the slug in its associatedrecess from under the stack of slugs, placing a second continuous stripof plastic sheet material in juxtaposition to said slug-containingrecessed first strip, maintaining the reduced pressure within thecavities until just prior to the emplacement of the second strip,raising the pressure in the cavities, thereby releasing the first stripand permitting it to shrink against the slugs as the cavities approach asealing position, sealing together and cutting out the portions of saidstrips surrounding each slug, reapplying a reduced pressure within thecavities to retain the capsules therein, pulling the net, consisting ofthe residual portions of the two strips, away from the capsules retainedin the cavity die roll, and ejecting the capsules from the cavities.

8. The method of claim 7 in Which the capsules are ejected from thecavities by applying air pressure to cap sule ejector pistons, raisingthe pistons and plugs attached thereto and forcing the capsules out ofthe cavities by these plugs.

9. The method of claim 7 in which the ejected capsules are ejected intoa moving stream of air and carried and tumbled by the moving stream ofair.

10. An apparatus for forming plastic film covered circular cross-sectionpre-compacted powder-filled capsules which comprises a rotating dieroll, a series or" cutting out rim surrounded capsule forming cavitiesin said die roll, means for supplying a first continuous strip ofplastic sheet material and feeding said strip onto the surface of saiddie roll, means for coating the slug contacting side of the strip withan inert innocuous coating substance, a slug magazine above the die rollfor feeding compacted powder slugs of approximately circularcross-section into strip-lined cavities in said die roll, a positionableslug retainer insertable into the channel in the magazine whereby thefeeding of slugs through the magazine may be interrupted, apertures inthe cover of said magazine to permit mis-aligned slugs to falltherethrough under the influence of vibration, means for collecting thefallen slugs for re-use, means for feeding slugs into the magazinecomprising a bowl feeder, a vibrator for vibrating said feeder,

a loose mounting for the slug magazine, and a slug feeding tube slightlylarger than the diameter of the slugs from said feeder to said magazine,means comprising a seal roll for supplying a second continuous strip ofplastic sheet material and placing said second strip in juxtaposition tothe slug containing first strip, means integral with said seal roll formaintaining the seal roll at temperature slightly elevated above the dieroll temperature, means for coating the slug contacting side of secondstrip with an inert innocuous coating substance, means for rotating saidrolls at the same'surface speed in contact with each other therebysealing together and cutting out the portions of the two strips adjacentthe slugs, a suction passage connected to the interior of each cavity inthe die roll, a source of vacuum, valve means for connecting saidpassage to said source prior to the passage of the cavity under the slugmagazine and maintaining said connection until just prior to the time atwhich the sealing together and cutting out occurs and releasing thevacuum during the sealing together and cutting out, thereby permittingthe strips to more closely contact the strip, means for adjusting thevacuum release point, means for re-applying the vacuum in the cavitiesafter the sealing and cutting out operation, thereby retaining thecapsules in the cavities, means for stripping the residual net from thecapsule containing die roll, means for ejecting the capsules from thedie roll into a capsule receiving housing, and an air blast to pick upand convey the capsules to a desired location.

11. An apparatus for forming plastic film covered precompactedpowder-filled capsules which comprises a retating die roll, a series ofcapsule forming cavities in said die roll, means for supplying a firstcontinuous strip of plastic sheet material and feeding said strip ontothe surface of said die roll, means for depressing said strip into saidcavities, a slug magazine to support a stack of slugs in contacting,oriented relationship above the die roll with the bot-tom slug incontact with said strip for feeding compacted powder slugs intostrip-lined cavities in said die roll, means for feeding slugs into saidmagazine and for vibrating said magazine, means comprising a seal rollfor supplying a second continuous strip of plastic sheet material andplacing said second strip in juxtaposition to the slug containing firststrip, means for rotating said rolls at the same surface speed incontact with each other and means on the rolling surfaces of said rollsto seal together around the slugs and cut out from the strips theportions of the strips adjacent the slugs, thereby forming film coveredpre-compacted powder filled capsules.

12. The apparatus of claim 11 in which the means for feeding the slugsinto the magazine comprises a bowl feeder, a vibrator for vibrating saidfeeder, and a slug feeding tube slightly larger than the diameter of theslugs from said feeder to said magazine.

13. The apparatus of claim 12 which comprises a loose mounting for theslug magazine so that the magazine is vibrated by the bowl feeder actingthrough the slug feeding tube.

14. The apparatus of claim 11 in which the means for depressing thestrip comprises a suction passage connected to the interior of thecavity, a source of vacuum, and valve means for connecting said passageto said source prior to the passage of the cavity under the slugmagazine, said valve means including means for maintaining saidconnection until just prior to the time at which the sealing togetherand cutting out occurs, and releasing the vacuum during the sealingtogether and cutting out, thereby permitting the strips to more closelycontact the slug.

15. The apparatus of claim 14 comprising means for adjusting the vacuumrelease point, whereby the degree of contact of the strips with the slugmay be varied.

16. The apparatus of claim 14 comprising means for reapplying the vacuumin the cavities after the sealing and cutting out operation, therebyretaining the capsules in the cavities, and means for stripping theresidual net from the capsule containing die roll.

17. The apparatus of claim 16 which comprises means.

for ejecting the capsules from the die roll into a capsule receivinghousing, and an air blast to pick up and convey the capsules to aselected location.

18. An apparatus for forming plastic film covered circular cross-sectionpre-compacted powder-filled capsules which comprises a rotating dieroll, in said die roll a series of capsule forming cavities of a depthless than the diameter of a slug plus twice the film thickness, acutting out rim surrounding each cavity, means for supplying a firstcontinuous strip of plastic sheet material and feeding said strip ontothe surface of said die roll, means for depressing said strip into saidcavities, a slug magazine to support a stack of slugs in contacting,oriented relationship above the die roll with the bottom slug in contactwith said strip for feeding compacted powder slugs of approximatelycircular cross-section into strip-lined cavities in said die roll, meansfor feeding slugs into said magazine and for vibrating said magazine,means comprising a seal roll for supplying a second continuous strip ofplastic sheet material and placing said second strip in juxtaposition tothe slug containing first strip depressions in said seal roll, below thegenerally circular cylindrical surface of the roll, of a pattern tomatch the cavities in the die roll, and of a depth equal to at leastthat amount by which the maximum diameter of the slugs plus twice thefilm thickness exceeds the cavity depth, and means for rotating saidrolls at the same surface speed in contact with each other therebysealing together and cutting out the portions of the two strips adjacentthe slugs.

19. The apparatus of claim 18 comprising a vacuum passage to eachdepression in the seal roll, and vacuum means, connectable to saidpassage, to draw the said second strip into said depression and intoheat transfer relationship with that portion of the seal roll in the depression.

20. An apparatus for forming plastic film covered circular cross-sectionpre-compacted powder-filled capsules which comprises a rotating dieroll, in said die roll a series of capsule forming cavities of a depthequal to at least the maximum diameter of the slugs plus twice the filmthickness, a cutting out rim surrounding each cavity, means forsupplying a first continuous strip of plastic sheet material and feedingsaid strip onto the surface of said die roll, means for depressing saidstrip into said cavities, a slug magazine to support a stack of slugs incontacting, oriented relationship above the die roll with the bottomslug in con tact with said strip for feeding compacted powder slugs ofapproximately circular cross-section into strip-lined cavities in saiddie roll, means for feeding slugs into said magazine and for vibratingsaid magazine, means comprising a smooth cylindrical surface seal rollfor supplying a second continuous strip of plastic sheet material andplacing said second strip in juxtaposition to the slug-containing firststrip and means for rotating said rolls at the same surface speed incontact with each other thereby sealing together and cutting out theportions of the two strips adjacent the slugs.

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